Recommendations on A engine 2 stage rocket?

Looking for small engine A size two (or three) Stage rocket. My last one, Estes Astron Elliptic II, has been such a kick in the pants! But has been getting gunked up after launches and the engines are getting harder and harder to remove after flights. I'm on to a Comanche 3 mini now, but I suspect it'll be the same problems as before. Thanks!

https://www.erockets.biz/semroc-flying-model-rocket-kit-firefly-kv-31/

or:
https://www.erockets.biz/semroc-flying-model-rocket-kit-excalibur-kv-43/
with this
https://www.erockets.biz/semroc-booster-kit-8-for-excalibur-and-others-sem-km-3/

https://www.erockets.biz/semroc-flying-model-rocket-kit-shrike-sem-kv-37/

some 320 grit sandpaper wrapped around a dowel will usually clean out the crud.
Rex

Engine (or "motor") tubes should remain clean on the inside because no exhaust should reach the inside of those tubes where the motor is installed.

If you are getting crud build up, then your upper stage motor probably does not have the masking tape installed around the top. When you install it in the middle, you have two potential problems:
1) the motor is swollen in the middle from the propellant and when the propellant is used, the cardboard casing can 'relax' and get smaller allowing the motor to eject. An ejecting motor can be fatal for the rocket or it can leave a large amount of gunk behind as it blows out the back. The top of the motor will not change size, so putting the masking tape around the top is best as the friction fit will not change after firing.
2) If you put tape in the middle, some of the ejection charge can blow down between the inside of the motor tube and the outside of the motor (until it reaches the tape in the middle. This will crud-up the upper inside portion of the motor tube.

Finally, using the wrong tape will leave adhesive crud behind. I've seen the five-times-as-expensive blue painters tape leave gooey adhesive behind. IT is crappy tape as it is designed to not stick firmly (which is why it is used for masking paint).

drew said:

Looking for small engine A size two (or three) Stage rocket. My last one, Estes Astron Elliptic II, has been such a kick in the pants! But has been getting gunked up after launches and the engines are getting harder and harder to remove after flights. I'm on to a Comanche 3 mini now, but I suspect it'll be the same problems as before. Thanks!

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